This invention concerns a power transmission device equipped with a plurality of prime movers, such as a gasoline engine, motor, etc., and, in particular, concerns a power transmission device with which the shift shock is reduced or eliminated by control of the speed stages and the prime movers.
Inventions disclosed in Japanese laid-open patent publication No. Hei 9-158998, etc. are known as prior arts of a power transmission device equipped with an engine and a motor. The invention discloses a vehicle driving device, which is equipped with an engine, a motor generator, a transmission, and a planetary gear that is connected to the engine via a starting clutch and is connected to the motor generator and transmission, and a control device for this vehicle driving device. This vehicle driving device is characterized in that the planetary gear is used as a synthesizing and distributing mechanism for the driving forces of the engine and the motor and in that the motor generator is driven prior to the engagement of the starting clutch in order to lessen the generation of inertia torque due to the lagging of the startup of the rotation of the motor generator.
However, the invention disclosed in Japanese laid-open patent publication No. Hei 9-158998 only prevents the lagging of the increase in rotation of the motor generator at the time of startup and could not lessen the shift shock that occurs in the process of shifting between various speed stages, such as from low gear to second speed, second speed to third speed, etc.
An object of this invention is thus to reduce or eliminate the shift shock in the take-off process and in the process of shifting between various speed stages in a power transmission device of a device having a plurality of prime movers, such as a gasoline engine, motor, etc.
In order to achieve the above object, this invention provides a power transmission device that is arranged so that in the shifting process, the inertia torques and output torques of a first prime mover and a second prime mover cancel each other out, thereby reducing the shift shock.
That is, the first aspect of this invention provides in a power transmission device of a device having a first prime mover and a second prime mover as drive sources, a power transmission device characterized in being arranged so that the respective inertia forces of the first prime mover and the second prime mover cancel each other out in the process of shifting from a first speed stage to a second speed stage.
By the above arrangement, the inertia force of the first prime mover and the inertia force of the second prime mover cancel out to enable reduction of the shift shock.
The second aspect of this invention provides an arrangement characterized in that in the process of shifting from the first speed stage to the second speed stage, the increase or decrease in the rotation speed of the first prime mover is the reverse of the increase or decrease in the rotation speed of the second prime mover.
With a vehicle equipped with just a single prime mover, since the rotation speed of the prime mover changes in the process of shifting, the shift shock is reduced by connecting the output shaft and the prime mover after completion of the change or by connecting gradually in the connection process. With the invention of the second aspect, the shift shock can be reduced or eliminated in a device having at least two prime movers by connecting a gear, etc., in a manner such that when the rotation speed of one of the prime movers drops during the shifting process, the rotation speed of the other prime mover increases, thereby enabling the excess inertia energy of one prime mover to be absorbed by the kinetic energy of the other prime mover.
The third aspect of this invention provides a power transmission device as set forth in the second aspect, wherein the shifting from the first speed stage to the second speed stage of the first prime mover and the shifting from the first speed stage to the second speed stage of the second prime mover are carried out substantially simultaneously.
With the invention of the second aspect, when a deviation in timing occurs between the shifting of one of the prime movers and the shifting of the other prime mover, the inertia energies of both prime movers will not be canceled out when only one or the other prime mover is undergoing the shifting process. It is thus preferable for the rotation speed to change as simultaneously as possible. Thus with a power transmission device, with which control is performed as set forth in the third aspect, the shift shock can be reduced or eliminated more effectively.
The fourth aspect of this invention provides a power transmission device as set forth in the second aspect, wherein
at least one of either the first prime mover or second prime mover is a motor and, in the process of shifting from the first speed stage to the second speed stage, the output torque of the motor is controlled so that the inertia torque of the driving parts at the first prime mover side and inertia torque of the driving parts at the second prime mover side cancel each other out before and after the shift.
The fifth aspect of this invention provides a power transmission device as set forth in the fourth aspect, wherein
the shifting from the first speed stage to the second speed stage of the first prime mover and the shifting from the first speed stage to the second speed stage of the second prime mover are carried out substantially simultaneously.
In comparison to a gasoline engine and other types of prime movers, a motor is good in output torque response and is more easy to control. Thus by using a motor as one of the prime movers and controlling the output torque of the motor so that the inertia torque during the shifting of one of the prime movers is canceled out by the motor, which is the other prime mover, the shift shock can be eliminated substantially completely. There are cases where the output torque of a motor must be generated and cases where the output torque must be made to act as a load for use in regenerative power generation, etc.
With a power transmission device, with which control is performed as set forth in the fifth aspect, the shift shock can be reduced or eliminated more effectively.
The sixth aspect of this invention provides a power transmission device as set forth in the first aspect, wherein
in the process of shifting from the first speed stage to the second speed stage, control is performed so that a torque that cancels out the inertia torque of one of the prime movers is output by the other prime mover.
By this arrangement, since the inertia torque during the shifting of one of the prime movers will be canceled out by the output of the other prime mover as in the case of the invention of the fourth aspect, the shift shock can be eliminated substantially completely.
The seventh aspect of this invention provides a power transmission device as set forth in the first aspect, wherein the power transmission device has a planetary gear set, a prime mover, which is connected to the respective rotating elements of the planetary gear set, a motor, and an output shaft, and
in the process of shifting from the first speed stage to the second speed stage, the increase or decrease in the rotation speed of the prime mover is in a reverse relationship with respect to the increase or decrease in the rotation speed of the motor and the output of the motor is controlled so that the inertia torques of the prime mover and the motor cancel each other out.
By this arrangement, since the inertia torque during the shifting of one of the prime movers will be canceled out by the output of the other prime mover as in the case of the invention of the fourth aspect, the shift shock can be eliminated substantially completely. Also, the timing of the shifting of the prime mover and the shifting of the motor can be adjusted mechanically.
The eighth aspect of this invention provides a power transmission device as set forth in the first aspect, wherein the power transmission device is equipped with a planetary gear set, a first transmission part, a prime mover, which is connected to the planetary gear set via the first transmission part, a motor and a second transmission part, which are connected to the planetary gear set, and an output shaft, which is connected to the first transmission part and second transmission part,
the second transmission part is connected to one rotating element, among the planetary gear""s three rotating elements of sun gear, ring gear, and carrier, which is selected so that when the one rotating element is fixed, the other two rotating elements rotate in mutually opposite directions, and each of the prime mover and motor is connected to one of the two rotating elements.
With such a power transmission device, by means of the first transmission part, the rotation speed of the output shaft is transmitted to the prime mover to change the rotation speed of the prime mover and this change of rotation speed of the prime mover changes, via the planetary gear set, the rotation speed of the motor. Also, since the prime mover and the motor are made to rotate in mutually opposite directions when the second transmission part is fixed, the increase or decrease in the rotation speed of the prime mover and the increase or decrease in the rotation speed of the motor will be in a mutually reversed relationship when the second transmission part, which is connected to the output shaft, is rotating at constant rotation speed. Since the inertia torque of the prime mover and the inertia torque of the motor are thus made to cancel each other out by the above-described relationship in the process wherein the rotation of the output shaft increases or decreases the rotation speed of the prime mover via the first transmission part and the change of rotation speed of the prime mover increases or decreases the rotation speed of the motor, the shift shock is reduced.
The ninth aspect of this invention provides a power transmission device as set forth in the first aspect, wherein the power transmission device is equipped with a planetary gear set, a first transmission part, a prime mover, which is connected to the planetary gear set via the first transmission part, a motor and a second transmission part, which are connected to the planetary gear set, and an output shaft, which is connected to the first transmission part and second transmission part,
the second transmission part is connected to one rotating element, among the planetary gear""s three rotating elements of sun gear, ring gear, and carrier, which is selected so that when the one rotating element is fixed, the other two rotating elements will rotate in mutually opposite directions, each of the prime mover and the motor is connected to one of the two rotating elements, and
in the process of shifting from the first speed stage to the second speed stage, the first transmission part and the second transmission part are controlled so as to be actuated substantially simultaneously and the output of the motor is controlled so that the inertia torques of the prime mover and the motor cancel each other out.
With such a power transmission device, by means of the first transmission part, the rotation speed of the output shaft is transmitted to the prime mover to change the rotation speed of the prime mover and this change of rotation speed of the prime mover changes, via the planetary gear set, the rotation speed of the motor. Also, since the prime mover and the motor are made to rotate in mutually opposite directions when the second transmission part is fixed, the increase or decrease in the rotation speed of the prime mover and the increase or decrease in the rotation speed of the motor will be in a mutually reversed relationship when the second transmission part, which is connected to the output shaft, is rotating at constant rotation speed. Since the inertia torque of the prime mover and the inertia torque of the motor are thus made to cancel each other out by the above-described relationship in the process wherein the rotation of the output shaft increases or decreases the rotation speed of the prime mover via the first transmission part and the change of rotation speed of the prime mover increases or decreases the rotation speed of the motor, the shift shock is reduced. Furthermore, since the first transmission part and the second transmission part are actuated substantially simultaneously, the generation and canceling out of the inertia torques occur substantially simultaneously, and since the output of the motor is controlled so that the part of the inertia torque that could not be canceled out completely will be canceled out, the shift shock can be practically eliminated.
In the claims and the specification, xe2x80x9cprime moverxe2x80x9d shall include motors. Also, xe2x80x9cconnectionxe2x80x9d shall refer to connection by gears, etc., connection by a shaft, and other conditions enabling the transmission of power.
The shift xe2x80x9cfrom a first speed stage to a second speed stagexe2x80x9d is not limited to a shift from the low gear to the second speed gear but refers to a shift from a certain gear to another gear and thus includes a shift from the second speed gear to the third speed gear, a shift from the fourth speed gear to the second speed gear, etc.
Also, though xe2x80x9cplanetary gear setxe2x80x9d shall refer to a gear set having a sun gear, ring gear, and carrier, the gear set may be comprised of just a single planetary gear (pinion gear) or may have a plurality of planetary gears, in other words, two or more planetary gears. In the case of a planetary gear set comprised of one planetary gear, the carrier corresponds to being the rotating element that is connected to the second transmission part in the invention of the eighth aspect or the ninth aspect and the prime mover or the motor may be connected to either the sun gear or the ring gear. Also, in the case of a planetary gear set comprised of two planetary gears, the ring gear carrier corresponds to being the rotating element that is connected to the second transmission part in the invention of the eighth aspect or the ninth aspect and the prime mover or the motor may be connected to either the carrier or the sun gear.
As has been described in detail above, this invention provides the following significant effects.
With the inventions of the first and second aspects, since the inertia torque of the first prime mover and the inertia torque of the second prime mover cancel each other out in the process of shifting in a vehicle, shift shock can be reduced.
With the invention of the third aspect, by performing the shifting operations of the first prime mover and the second prime mover simultaneously, shift shock can be reduced more effectively.
With the invention of the fourth aspect, since a motor, which is good in torque controllability, is used as at least one of the prime movers and the inertia torque that could not be canceled out completely is canceled out further by control of the motor torque, shift shock can be practically eliminated.
With the invention of the fifth aspect, by performing the shifting operations of the first prime mover and the second prime mover simultaneously, shift shock can be reduced more effectively.
With the invention of the sixth aspect, since in the process of shifting in a vehicle, control is performed so that a torque, which will cancel out the inertia torque of one of the prime movers, is output by the other prime mover, shift shock can be reduced.
With the inventions of the seventh to ninth aspects, since the rotation speeds of a prime mover and a motor can be varied while keeping the rotation speed of the output shaft fixed by means of a power transmission device, with which the prime mover, motor, and output shaft are connected via planetary gear set, a power transmission device of this invention can be arranged readily, and furthermore, with the inventions of the seventh and ninth aspects, since control is performed so that the inertia torque in the shifting process will be canceled out by means of a motor that is good in controllability, shift shock can be practically eliminated.